Re: [PATCH] Remove MAX_REGISTER_SIZE from regcache.c

[Alan Hayward <Alan dot Hayward at arm dot com>]

> On 21 Apr 2017, at 15:01, Yao Qi <qiyaoltc@gmail.com> wrote:
> 
> On Mon, Apr 10, 2017 at 9:59 AM, Yao Qi <qiyaoltc@gmail.com> wrote:
>> 
>> This patches removes the 2nd argument of regcache_restore, because it
>> is only called by regcache_cpy.  In regcache_cpy, if regcache_restore
>> is called, dst is not readonly, but src is readonly.  So this patch
>> adds an assert that src is readonly in regcache_restore.
>> regcache_cook_read read everything from a readonly regcache cache
>> (src)'s register_buffer, and register status is from src->register_status.
>> 
>> gdb:
>> 
>> 2017-04-07  Yao Qi  <yao.qi@linaro.org>
>> 
>>        * regcache.c (regcache_restore): Remove argument 2.  Replace
>>        argument 3 with regcache.  Get register status from
>>        src->register_status and get register contents from
>>        register_buffer (src, regnum).
>>        (regcache_cpy): Update.
>> 
> 
> Tested it again on x86_64-linux.  Pushed it in.
> 
> -- 
> Yao (齐尧)

Ok, this leaves the following in regcache.c.

Tested on a --enable-targets=all using make check with board files
unix and native-gdbserver.

Ok to commit?

Alan.

2017-04-26  Alan Hayward  <alan.hayward@arm.com>

	* regcache.c (regcache_save): Avoid buffer use.
	(regcache_dump): Avoid buffer use.



diff --git a/gdb/regcache.c b/gdb/regcache.c
index f9bf992197b8e7bdc3cfc6fc3bafbcf928c49df9..6c1c8b9ee373d8998f771d756542f59e2adde8ff 100644
--- a/gdb/regcache.c
+++ b/gdb/regcache.c
@@ -337,7 +337,6 @@ regcache_save (struct regcache *dst, regcache_cooked_read_ftype *cooked_read,
 	       void *src)
 {
   struct gdbarch *gdbarch = dst->descr->gdbarch;
-  gdb_byte buf[MAX_REGISTER_SIZE];
   int regnum;

   /* The DST should be `read-only', if it wasn't then the save would
@@ -356,17 +355,13 @@ regcache_save (struct regcache *dst, regcache_cooked_read_ftype *cooked_read,
     {
       if (gdbarch_register_reggroup_p (gdbarch, regnum, save_reggroup))
 	{
-	  enum register_status status = cooked_read (src, regnum, buf);
+	  gdb_byte *dst_buf = register_buffer (dst, regnum);
+	  enum register_status status = cooked_read (src, regnum, dst_buf);

-	  if (status == REG_VALID)
-	    memcpy (register_buffer (dst, regnum), buf,
-		    register_size (gdbarch, regnum));
-	  else
+	  if (status != REG_VALID)
 	    {
 	      gdb_assert (status != REG_UNKNOWN);
-
-	      memset (register_buffer (dst, regnum), 0,
-		      register_size (gdbarch, regnum));
+	      memset (dst_buf, 0, register_size (gdbarch, regnum));
 	    }
 	  dst->register_status[regnum] = status;
 	}
@@ -1334,7 +1329,6 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
   int footnote_register_offset = 0;
   int footnote_register_type_name_null = 0;
   long register_offset = 0;
-  gdb_byte buf[MAX_REGISTER_SIZE];

 #if 0
   fprintf_unfiltered (file, "nr_raw_registers %d\n",
@@ -1461,8 +1455,8 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
 	    fprintf_unfiltered (file, "<unavailable>");
 	  else
 	    {
-	      regcache_raw_read (regcache, regnum, buf);
-	      print_hex_chars (file, buf,
+	      regcache_raw_update (regcache, regnum);
+	      print_hex_chars (file, register_buffer (regcache, regnum),
 			       regcache->descr->sizeof_register[regnum],
 			       gdbarch_byte_order (gdbarch));
 	    }
@@ -1475,9 +1469,30 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
 	    fprintf_unfiltered (file, "Cooked value");
 	  else
 	    {
+	      const gdb_byte *buf = NULL;
 	      enum register_status status;
+	      struct value *value = NULL;
+
+	      if (regnum < regcache->descr->nr_raw_registers)
+		{
+		  regcache_raw_update (regcache, regnum);
+		  status = regcache_register_status (regcache, regnum);
+		  buf = register_buffer (regcache, regnum);
+		}
+	      else
+		{
+		  value = regcache_cooked_read_value (regcache, regnum);
+
+		  if (!value_optimized_out (value)
+		      && value_entirely_available (value))
+		    {
+		      status = REG_VALID;
+		      buf = value_contents_all (value);
+		    }
+		  else
+		    status = REG_UNAVAILABLE;
+		}

-	      status = regcache_cooked_read (regcache, regnum, buf);
 	      if (status == REG_UNKNOWN)
 		fprintf_unfiltered (file, "<invalid>");
 	      else if (status == REG_UNAVAILABLE)
@@ -1486,6 +1501,12 @@ regcache_dump (struct regcache *regcache, struct ui_file *file,
 		print_hex_chars (file, buf,
 				 regcache->descr->sizeof_register[regnum],
 				 gdbarch_byte_order (gdbarch));
+
+	      if (value != NULL)
+		{
+		  release_value (value);
+		  value_free (value);
+		}
 	    }
 	}